The role of albumin in the maintenance of colloid pressure and in the transport of solutes is well known. Little is known, however, of the role of albumin in interfacial biochemistry, particularly at or near the endothelial surfaces and the surfaces of other materials. There is growing evidence that albuminated surfaces are often more blood tolerable than non albumin with respect to: interfacial potentials; interfacial free energy; ion-binding and local pH and pIon effects; solute- and protein and other macromolecule adsorption. Albumin surfaces prepared by adsorption and by covalent attachment will be examined. Biodegradation and biostability will be studied in vivo and in vitro. The blood tolerability of albuminated surfaces will be examined with respect to both coagulation and thrombosis. Flow effects will be included in the studies. It is expected that practical surfaces which are truly blood tolerable will result from this work. It is further expected that knowledge of such interfacial behavior will be important in the understanding of atherosclerosis, cell adhesion to the vessel wall, and metastasis.